ALMATY (Reuters) - Kazakh state prosecutors said on Wednesday they will re-investigate the 2004 death of a prominent banker after the man convicted of accidentally killing him said he had in fact been hired to do so by Mukhtar Ablyazov, a former oligarch turned opponent of President Nursultan Nazarbayev.

The Central Asian nation’s government has accused Ablyazov, who has been living in France, of embezzling billions of dollars from a local bank he used to run. A French court last year ruled against extraditing him, however, and set him free.

The new probe may lead to a fresh extradition request from the former Soviet republic, setting the stage for another prolonged legal battle in European courts.

Ablyazov, once a wealthy businessman who became a government minister, led an opposition political movement in the early 2000s until being convicted on corruption charges in 2002.

Nazarbayev pardoned him in 2003. But Ablyazov fell out with the strongman leader again in 2009 when the government nationalized BTA, Kazakhstan’s biggest bank at the time, of which Ablyazov was the chairman and majority shareholder.

He then fled Kazakhstan, whose authorities have since unsuccessfully tried to have him brought back to the country on fraud and embezzlement charges while also seeking to seize his personal assets.

On Tuesday, a businessman now in prison for an unrelated crime claimed in a television documentary that he had murdered Ablyazov’s former associate in 2004 in a “hit job” ordered by the oligarch.

At the time, the death was ruled involuntary manslaughter as the killer said he had accidentally shot banker Yerzhan Tatishev during a hunting trip. Tatishev was the chief executive of BTA; shortly after his death Ablyazov became the bank’s chairman.

The Prosecutor General’s office said on Wednesday it was reopening the case and reclassifying it as murder.

Although the prosecutors’ statement did not mention Ablyazov, the latter accused the government in a Facebook post on Wednesday of forcing the alleged killer to falsely testify against him.

Since a French court set him free last December, Ablyazov has regularly used social networks to criticize Nazarbayev, who has run the oil-rich nation of 18 million since 1989.